1. Field of the Invention
The present invention relates to an electronic endoscope system including a scope having a solid-state image sensor provided at a distal end thereof to generate image-pixel signals, an image-signal processing unit that produces a video signal on the basis of the image-pixel signals, and a TV monitor for reproducing and displaying an image in accordance with the video signal.
2. Description of the Related Art
In general, in such an electronic endoscope system, a component-type color video signal is produced on the basis of image-pixel signals obtained from a solid-state image sensor, such as a CCD (charge-coupled device) image sensor, to reproduce an image of high quality on a TV monitor. Usually, the component-type color video signal is composed of three-primary-color video signal components and a compound-synchronizing-signal component which includes various synchronizing signals, such as a horizontal synchronizing signal, a vertical synchronizing signal and so on.
As is well known, the compound-synchronizing-signal component is produced as a voltage signal, and the peak-to-peak level of the voltage signal is standardized to, for example, 4 volts. Thus, a medical TV monitor, used in the electronic endoscope system, is designed in accordance with the compound-synchronizing-signal component exhibiting the peak-to-peak level of 4 volts.
Since the medical TV monitor is expensive, a domestic TV monitor may be frequently substituted for the medical TV monitor. However, domestic TV monitors are not designed so as to accept the compound-synchronizing-signal component exhibiting the peak-to-peak level of 4 volts. Thus, the domestic monitors cannot properly function and display an image when being connected to an image-signal processing unit.
Specifically, after introducing an electronic endoscope system with a medical TV monitor into a medical facility, when the medical TV monitor is replaced by a domestic TV monitor, or when a domestic TV monitor is added to the introduced electronic endoscope system, a problem will occur.
Therefore, an object of the present invention is to provide an electronic endoscope system comprising a scope having a solid-state image sensor provided at a distal end thereof to generate image-pixel signals, and an image-signal processing unit that produces a video signal on the basis of the image-pixel signals, wherein a peak-to-peak level of the synchronizing-signal component of the video signal can be manually and easily altered such that various types of TV monitors can accept the video signal.
In accordance with the present invention, there is provided an electronic endoscope system including a scope having a solid-state image sensor provided at a distal end thereof to generate image-pixel signals, and an image-signal processing unit that produces a video signal based on the image-pixel signals. The electronic endoscope comprises, an alteration system that alters a peak-to-peak level of a synchronizing-signal component of the video signal, an manual setting system that manually operates the alteration system to perform the alteration of the peak-to-peak level of the synchronizing-signal component; an indicator system that indicates a degree of the alteration of the peak-to-peak level of the synchronizing-signal component during the operation of the manual setting system, and an output terminal that outputs the synchronizing-signal component having the peak-to-peak level defined by the alteration system.
Preferably, the manual setting system is provided in a housing of the image-signal processing unit so as to be accessible by a suitable manual tool.
The alteration system may comprise a voltage-controlled amplifier, an amplification factor of which is regulated in accordance with a level of a voltage signal applied thereto. In this case, the manual setting system may comprise a variable resistor that adjusts the level of the voltage signal.
The indicator system may include an indicator lamp visually provided at a suitable location of a housing of the image-signal processing unit, and a lamp driver system that controls lighting of the indicator lamp in accordance with the degree of alteration of the peak-to-peak level of the synchronizing-signal component. Preferably, the indicator lamp includes at least two light-emitting sources, and the driver system controls not only turn-ON and turn-OFF of the light-emitting sources but also brightness of the light-emitting sources in accordance with the degree of the alteration of the peak-to-peak level of the synchronizing-signal component. Also preferably, the respective light-emitting sources emit different monochromatic light.
The lamp driver system may include an ON/OFF switch element that controls supply of electrical power from the lamp driver system to the indicator lamp, and a timer system that turns OFF the ON/OFF switch element after a predetermined time is elapsed from a time at which the ON/OFF switch is turned ON.
Optionally, the lamp driver system may include a tool-detection system that detects whether access to the manual setting system by the manual tool is made, and the lamp driver system is allowed to feed electric power to the indicator lamp only when the access to the manual setting system by the manual tool is detected by the tool-detection system.
The lamp driver system may further include an ON/OFF switch element that controls the supply of the electrical power from the lamp driver system to the indicator lamp, and the ON/OFF switch is turned ON only when the access to the manual setting system by the manual tool is detected by the tool-detection system.
The manual setting system may include a portion which is manually operated by a suitable manual tool, and which is arranged such that the manual tool is operable without interfering with a signal cable extending from the output terminal.